The Solvita field test enables any person to monitor as-is or natural microbial respiration, the turnover of soil-carbon under circumstances unaffected by lab processing. To do this, one prepares a soil sample without drying or grinding. When measuring soil respiration in this way, key factors which influence the outcome include moisture and temperature, temperature being the most important. Soils are often sampled at one temperature and then tested at another. In order to help illustrate how these factors influence Solvita soil test results, Woods End offers a Solvita Calculator. The algorithm is based on the well-known Arrhenius Equation that relates biochemical reactions to temperature. We’ve modified it with soil moisture and a season-length factor.
The are two Calculators, Basic and Advanced one which requires less input than the other. The Advanced calculator allows you to adjust the recommendations by adding information about seasonal factors. The calculator supplies an estimated CO2-C result and an estimated nitrogen mineralization that will occur over the course of your growing season given the temperature, moisture and season length which you input.
To use the calculator:
- Select your required unit of measurement (standard “Imperial” or metric)
- Enter your information: Solvita CO2 number, growing season length, and your average soil temperature for the growing season.
- Advanced Calculator: Additional soil properties can be input by clicking the “Show Advanced Calculator” button. This allows you to input available (soil-test) nitrogen and it will be subtracted from estimated crop requirement. If soil C:N is unknown the calculator assumes 12. Increase the C:N value if lots of crop stubble are present. You may use any suitable factor.
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|Solvita Field Test Color Number, 0 to 6.5||color|
|Your average soil temperature|| °|
|Number of days in your crop's growing season||days|
|Adjusted CO2-C based on the entered soil temp above|
|Likely Organic Nitrogen Mineralized over growing season|
|Dollars Saved due to Biological Nitrogen|
|Soil Carbon : Nitrogen C:N Ratio (if known)|
|Available Nitrate-N ppm or mg/kg (from soil test result)||PPM|
|Extracted Ammonium-N ppm or mg/kg (from soil test result)||PPM|
|Crop Nitrogen Requirements|
|Days your soil is too dry (Wilt Point)||days|
|Days your soil is too wet (Saturated)||days|
|Days your soil is ideal moisture|
|Potentially Mineralizable N for Season|
|Additonal Nitrogen to meet crop requirements|
|Nitrogen Savings Per|
Notes to the Guide:
Sequestered Carbon: this calculates the quantity of soil carbon associated with the measured field CO2 respiration rate. We’ve made some assumptions about the annual decay rate of carbon to make this useful.